Method for gas assisted energy beam engraving of a target object

ABSTRACT

This invention relates to a method for gas assisted energy beam engraving of a target object. This invention employs and energy beam, such as a laser beam or an electron beam, to irradiate a target object in the presence of a selected gaseous environment in order to engrave a mark in the object.

REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.09/413,972, filed on Oct. 7, 1999.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a method for gas assisted energy beamengraving of a target object. This invention employs an energy beam,such as a laser beam or an electron beam, to irradiate a target objectin the presence of a selected gaseous environment in order to engrave amark in said object.

[0004] 2. Description of the Prior Art

[0005] Laser beams have been employed to engrave marks on the surface oftarget objects. Prior art methods of laser engraving have been carriedout in the ambient atmospheric environment.

[0006] Ambient environment laser engraving results in a limited degreeof contrast between the engraved mark and the background on which it isplaced, the speed with which the mark can be applied, and the number ofdifferent materials which can be marked.

[0007] The present invention provides an improved method for energy beamengraving, in which an energy beam, such as a laser beam, is used toengrave a target object in the presence of a selected gaseousenvironment. This improved method provides enhanced contrast, increasedreadability, increased marking speeds, and an increased number ofmaterials which can be marked by the energy beam.

SUMMARY OF THE INVENTION

[0008] The present invention is directed toward a method of gas assistedenergy beam engraving of a target object. This invention comprisesplacing a target object in a controlled gaseous environment, irradiatingthe target object with an energy beam at a sufficient power level andbeam size to engrave a mark in the target object, while the portion ofthe object being irradiated is present in the controlled gaseousenvironment. This method further comprises causing relative movement ata preselected speed between the energy beam and the target object duringirradiation.

DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a block diagram of a first embodiment of the presentinvention.

[0010]FIG. 2 is a block diagram of a second embodiment of the presentinvention.

[0011]FIG. 3 is a block diagram of a third embodiment of the presentinvention.

[0012]FIG. 4 is a block diagram of a preferred embodiment of covering atarget with a covering gas, using the method of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In a first embodiment, the present invention comprises placing atarget object in a controlled gaseous environment, as shown in block 10of FIG. 1. In preferred embodiments, the gaseous environment comprisesargon, nitrogen, oxygen, or carbon dioxide.

[0014] The invention further comprises irradiating the target objectwith an energy beam at a sufficient power level and beam size to engravea mark in the target object while the portion of the object beingirradiated is present in the controlled gaseous environment, as shown inblock 12 of FIG. 1. In a preferred embodiment, the target objectcomprises stainless steel, aluminum, or titanium. In another preferredembodiment, the target object is a ceramic.

[0015] In one preferred embodiment, the energy beam is a laser beam. Ina preferred embodiment, the laser is emitted from a Model LD-100 DesktopLaser Marker, available from Laser Marking Technologies, LLC ofLafayette, Colorado. In this embodiment, the laser beam is emitted at acurrent level of six to ten amperes. In another preferred embodiment,the laser is emitted at a current level of at least six amperes. Inanother preferred embodiment, the energy beam is an electron beam.

[0016] A second embodiment of the present invention is directed toward amethod for gas assisted laser engraving of a target object. Thisembodiment comprises irradiating a target object with a laser beam at asufficient power level and beam size to engrave a mark in the targetobject, as shown in block 20 of FIG. 2. This method further comprisescovering the surface of the target object which is being irradiated witha selected cover gas, simultaneously while the irradiation is takingplace, as shown in block 22 of FIG. 2. The term “cover gas,” as usedherein, refers to any reducing gas, inert gas, or oxidizing gas.Oxidizing gases facilitate oxidation reactions. Reducing gasesfacilitate reduction reactions.

[0017] In a preferred embodiment, the cover gas is ejected from anozzle. In another preferred embodiment, the cover gas is heavier thanthe gas composition which makes up the earth's atmosphere.

[0018] This method further comprises causing relative movement at apreselected speed between the laser beam and the target object, suchthat the engraved mark is a preselected pattern. This relative movementoccurs simultaneously with the irradiation, as shown in block 24 of FIG.2. This relative movement may take place by moving the laser inincremental steps, each step being no greater than 60 microns in size.

[0019] In a preferred embodiment, the relative movement comprises movinga laser which emits the laser beam. In the preferred embodiment usingthe Model LD-100 Desktop Laser Marker, the laser is moved at a speed ofup to three meters per second. The appropriate speed will be a functionof the target composition and the desired depth of engraving. In anotherpreferred embodiment, causing relative movement comprises moving thetarget object.

[0020] A third embodiment of the present invention is depicted in FIG.3. This embodiment comprises emitting a laser beam from a laser at asufficient power level and beam size to engrave a target object, asshown in block 30 of FIG. 3. This method further comprises moving thelaser in a preselected pattern to produce a preselected mark on thetarget object, as shown in block 32 of FIG. 3.

[0021] This embodiment of the invention further comprises covering thesurface of the target object which is being irradiated with a selectedcover gas, as shown in block 34 of FIG. 3. This step is carried outsimultaneously with the steps shown in blocks 30 and 32 of FIG. 3.

[0022] In a preferred embodiment, the covering comprises emitting thecover gas from a nozzle, as shown in block 36 of FIG. 4. The coveringfurther comprises moving the nozzle such that the cover gas is directedat the regions of the target object being irradiated, as shown in block38 of FIG. 4.

[0023] In a preferred embodiment, the cover gas comprises one or moregases selected from the group consisting of argon, nitrogen, oxygen, andcarbon dioxide.

[0024] The foregoing disclosure and description of the invention areillustrative and explanatory. Various changes in the size, shape, andmaterials, as well as in the details of the illustrative embodiments maybe made without departing from the spirit of the invention.

What is claimed is:
 1. A method for gas assisted energy beam engravingof a target object, comprising: a. placing at least a portion of thetarget object in a controlled gaseous environment; b. energizing asource of an energy beam with at least six amperes of current, theenergy beam further comprising a beam size sufficient to engrave a markin the target object to predetermined dimensions; c. irradiating adesired portion of the target object with the energy beam while thedesired portion of the target object being irradiated is present in thecontrolled gaseous environment; and d. causing relative movement betweenthe energy beam and the target object during the irradiating, themovement occurring in a predetermined manner to create a desiredengraved pattern in the target object.
 2. The method of claim 1 ,wherein the gaseous environment comprises reducing gases, inert gases,oxidizing gases, or combinations thereof.
 3. The method of claim 1 ,wherein the energy beam is a laser beam.
 4. The method of claim 1 ,wherein the target object comprises ceramics, stainless steel, aluminum,and titanium.
 5. A method for gas assisted laser engraving of a targetobject, comprising: a. placing at least a portion of the target objectinto a controlled gaseous environment; b. irradiating at least a portionof the target object in the controlled gaseous environment with a laserbeam from a laser, the laser drawing a current level of at least sixamperes, the laser beam further comprising sufficient power and beamdimensions to engrave a desired mark in the target object; c.simultaneously with the irradiating, covering a surface of the targetobject which is being irradiated with a predetermined cover gas; and d.simultaneously with the irradiating, causing relative movement betweenthe laser beam and the target object, at a preselected speed to create adesired pattern.
 6. The method of claim 5 , wherein the cover gas instep (c) is ejected from a nozzle in communication with a source ofcover gas and the controlled gaseous environment.
 7. The method of claim6 , further comprising moving the nozzle such that the cover gas isdirected at the surface of the target object being irradiated.
 8. Themethod of claim 5 , wherein the cover gas is heavier than the gascomposition which makes up the earth's atmosphere.
 9. The method ofclaim 5 , wherein step (d) further comprises moving a laser which emitsthe laser beam.
 10. The method of claim 5 , wherein step (d) furthercomprises moving the target object.
 11. The method of claim 5 , whereinthe cover gas comprises gases selected from the group of gassesconsisting of argon, nitrogen, oxygen, carbon dioxide, or combinationsthereof.
 12. The method of claim 5 , wherein the target object comprisesmetallic objects and ceramic objects.
 13. A system for engraving,comprising: a. a controlled gaseous environment; b. a target holderdisposed within the controlled gaseous environment, the target holderhaving sufficient size to support a target object to be engraved in thecontrolled gaseous environment; c. an energy beam device drawing atleast six amperes, the energy beam device able to generate an energybeam of predetermined dimensions that can be made to irradiate apredetermined portion of the target object; d. a source of cover gas;and e. an outlet for the cover gas in communication with the controlledgaseous environment and the source of cover gas.
 14. The system of claim13 further comprising a controllable energy beam moving device coupledto the energy beam device, the energy beam moving device having acontrollable incremental step movement of an approximately 60 micronstep size.
 15. The system of claim 13 further comprising a controllabletarget object moving device.
 16. The system of claim 13 wherein theenergy beam device is a laser.
 17. The system of claim 13 wherein theoutlet for the cover gas further comprises a nozzle in communicationwith the source of cover gas, the nozzle further capable of beingdirected at regions of the target object being irradiated.
 18. Thesystem of claim 13 , wherein the cover gas comprises gases selected fromthe group consisting of argon, nitrogen, oxygen, carbon dioxide, andcombinations thereof.